Sexual Segregation of Coastal Bottlenose Dolphins (Tursiops truncatus) in the Southwestern Gulf of Mexico

Morteo, Eduardo; Rocha‐Olivares, Axayácatl; Abarca-Arenas, Luis Gerardo

doi:10.1578/am.40.4.2014.375

Cited by 19 publications

(80 citation statements)

References 23 publications

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“…However, since the statistical distribution was skewed towards smaller aggregations (i. e. one third of the sightings were composed of solitary individuals and pairs) despite our inclusive definition (Figure 2), this value seems inconclusive. Morteo et al (2014) anticipated this for bottlenose dolphins within the same study area, and determined that many of these small aggregations were likely single sexed. This strongly suggests that the community may be divided into small social units that join in common activities (Campbell et al 2002).…”

Section: Discussionmentioning

confidence: 95%

“…Morteo et al (2012) pointed out the importance of boat traffic and fishing activities in the area, which seem to influence the presence and distribution of dolphins on a daily basis or even instantaneously (Constantine et al 2004;Lusseau et al 2006;Hernandez-Candelario 2009). Although many cetaceans seem to have habituated to certain levels of marine traffic, other evidence suggest that it may cause severe alterations in their behavior and in this case may promote the separation of group members, probably altering the social bonds within the community (Constantine et al 2004;Morteo et al 2012;Morteo et al 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Social and ecological pressures may dictate the temporality of the associations at different scales (McDonald and Carr 1989;Quintana-Rizzo 2006;Morteo et al 2014). For instance, some species are known to maintain strong permanent and even multilevel associations such as killer whales (Orcinus orca) and sperm whales (Physeter microcephalus; Bräger et al 1994;Whitehead et al 2012), whereas other like the spinner dolphin (Stenella longirostris) are very loose (Chilvers and Corkeron 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Several communities of the coastal form of this species are known to present segregation related to sex, age and reproductive status, thus the nature of their associations is highly variable (Wells et al 1987;Wells 1991;Connor et al 1992;Smolker et al 1992;Connor et al 2000;Quintana-Rizzo and Wells 2001;Morteo et al 2014). Living in social groups facilitates feeding, protecting against harassment, predation, enhances reproductive output, and promotes communication and learning (Bräger et al 1994).…”

Section: Introductionmentioning

confidence: 99%

“…Coastal bottlenose dolphins inhabiting the waters off Alvarado in the state of Veracruz have been studied intermittently since 1993 (García 1995) and reliable data on individual identities has been collected since 2002 (Del Castillo 2010;Morteo et al 2014). Many of these dolphins are known to associate and develop a range of activities, but little is known on how these animals interact and form groups, and if they do it with different purposes (Morteo 2011;García-Vital 2012).…”

Section: Introductionmentioning

confidence: 99%

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Inter-individual association levels correlate to behavioral diversity in coastal bottlenose dolphins (Tursiops truncatus) from the Southwestern Gulf of Mexico

Vital

Morteo

Serrano

et al. 2015

Therya

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Las asociaciones entre individuos se correlacionan con la diversidad de las conductas en delfines costeros (Tursiops truncatus) del Sureste del Golfo de MéxicoInter-individual association levels correlate to behavioral diversity in coastal bottlenose dolphins (Tursiops truncatus) from the Southwestern Gulf of Mexico Introduction: Societies in mammal species are influenced by intrinsic and extrinsic factors that affect the temporality of the associations among individuals. Coastal bottlenose dolphins generally live in small fluid aggregations variable in composition, but the nature of their associations is commonly unknown. Our goal was to determine if school size was influenced by dolphins' behavior, and if individuals associated to develop particular activities within the coastal waters of Alvarado, Mexico. Methods:In total, 80 boat-based surveys were conducted (2002 -2003 and 2006 -2009), where group size, behavior, and photo-identification data were collected. From 237 sightings and 2,021 dolphins the mean school size was 8.5 animals (s. d. = 8.6), but individuals and pairs were observed more frequently (33 %).Results: Temporal differences in school sizes and behavior conveyed with habitat seasonality (P < 0.05), but were inconsistent across years; thus short-term factors such as marine traffic and fisheries intensity were deemed important. Dolphins were commonly feeding (29 %) corresponding to groups of 4 -6 animals, whereas solitary individuals typically showed evasion (P < 0.01). Discussion and Conclusions:Association coefficients computed for 89 of the 232 identifiable dolphins proved not random only in 6 % of the 3,915 combinations (P < 0.05), and these coefficients were positively correlated to the diversity of activities developed by each dyad (P < 0.01), thus the nature of their associations in most cases (93 %) became richer with time. The community is likely formed by very small units that frequently exchange members; this may be due to large food availability and low predator abundance in the area, but also to avoid detection and threats posed by local artisanal fisheries.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Inter-individual association levels correlate to behavioral diversity in coastal bottlenose dolphins (Tursiops truncatus) from the Southwestern Gulf of Mexico

Vital

Morteo

Serrano

et al. 2015

Therya

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Bottlenose dolphins share fish farm areas while maintaining sexual segregation: Investigating group memberships through spatially and temporally explicit parameters

Bonizzoni¹,

Genov

Bearzi

2022

Aquatic Conservation

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Group membership is a key attribute of animal societies and central to the study of social structure in several taxa. However, social structure analyses are sensitive to the way data are collected and associations defined. In this study, a time–space method was used to investigate the social structure of common bottlenose dolphins Tursiops truncatus observed and photographed across 7 years in the semi‐enclosed Gulf of Corinth, Greece. Instead of adopting traditional group definitions, individuals were considered as being members of the same group if photographed within a specific time and space window. This approach can be applied post hoc across studies and can offer advantages under challenging sampling conditions (e.g. when dealing with groups spread over vast areas or when group membership is otherwise hard to assess). Dolphins were mostly found around coastal cage aquaculture facilities farming European sea bass Dicentrarchus labrax and gilthead seabream Sparus aurata. Dolphins formed clusters largely or entirely composed of individuals of the same sex, suggestive of sex‐based homophily. Habitat partitioning was not detected: there was substantial spatial overlap among dolphin clusters, with all individuals using a relatively small area in the northern portion of the Gulf, where most of the productive fish farms were located. Associations between females were stronger than those between males, and daughters tended to stay in the group of their mothers. Sex‐based social clustering may allow females and calves to limit interactions with potentially aggressive males, while individuals of both sexes benefit from prey concentrated around fish farms. Adaptation to foraging around farms can result in trade‐offs between the costs and benefits of nourishment and social interaction. This may have both positive or negative effects on the animals that should be considered in the context of ensuring their favourable conservation status.

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Movement Patterns of Odontocetes Through Space and Time

Bräger

2019

Ethology and Behavioral Ecology of Odontocetes

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Sexual Segregation of Coastal Bottlenose Dolphins (Tursiops truncatus) in the Southwestern Gulf of Mexico

Cited by 19 publications

References 23 publications

Inter-individual association levels correlate to behavioral diversity in coastal bottlenose dolphins (Tursiops truncatus) from the Southwestern Gulf of Mexico

Inter-individual association levels correlate to behavioral diversity in coastal bottlenose dolphins (Tursiops truncatus) from the Southwestern Gulf of Mexico

Bottlenose dolphins share fish farm areas while maintaining sexual segregation: Investigating group memberships through spatially and temporally explicit parameters

Movement Patterns of Odontocetes Through Space and Time

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